There has been considerable effort to develop various devices which include film layers which are ultimately to be applied to the skin of a host or patient. These various devices include, for example, bandages which are in the form of a film and can be substituted for conventional bandages.
By way of background, it should thus be understood that for centuries the common understanding of wound healing and treatment remained relatively static. There was a general understanding based on experience that open wounds were subject to contamination and infection. Beyond that, there was a perception that optimum healing occurred under the natural protective cover of dried wound exudate--a scab. As a result, dressing materials, typically composed of gauze or fabric, were used over both traumatic and surgical wounds to protect them from gross particulate contamination and to promote drying and scab formation.
Not until the early 1970's was it observed and published that, contrary to long established thought, wounds do in fact heal significantly faster and with less scar formation under a film which maintains a wellbalanced moist environment, such as that which naturally occurs under a blister.
This changed perception of the wound healing process, along with a widespread recognition of its commercial implications, led to the introduction beginning in 1981 of a new category of "moist environment" synthetic transparent adhesive dressings based on adhesive coated films extruded or cast from high moisture vapor permeable, elastomeric resins--initially polyurethanes. In the several years since their commercial introduction, these products have achieved the acceptance of the medical community based on both clinical performance and cost effectiveness.
An example of an adhesive medical or surgical dressing which includes a moisture-vapor-permeable pressure-sensitive adhesive material is disclosed in Hodgson, U.S. Pat. Nos. Re. 31,886 and 31,887. The adhesive medical or surgical dressing is specifically shown in FIG. 5 of these patents, and includes a dressing pad 18 on the adhesive side thereof. There are also a number of wound dressing products currently on the market. These include products such as wound dressings being sold by Ferris corporation of Burr Ridge, Ill., under the mark DYNAMERM.TM., which includes a backing layer, a liner layer, and a film layer therebetween within a sealed, tearable package. In this case, color-coded paper tabs are provided on either end of the carrier layer so that by pulling on a first such tab the carrier layer and the film layer are removed from the backing layer. The film can then be applied by pulling on the second tab after application to the skin. Removal of each tab, initiation of each step in this procedure, and assurance of a smooth transfer of the film cannot be guaranteed with this product, however. Other such wound dressings include products of The Kendall Company of Boston, Mass., sold under the mark POLYSKIN.TM., and Johnson & Johnson sold under the mark BIOCLUSIVE. Again, none of these products can easily and rapidly apply a film layer to the skin, and in particular they do not include any hinge means between the outer layers thereof.
There have also been considerable developments in connection with transdermal administration systems. These include Ciba-Geigy's TRANSDERM.RTM.-NITRO and TRANSDERM.RTM.-V systems which have been approved for transdermal administration of nitroglycerine and scopolamine, respectively. These prior devices for the controlled, continuous metering of drugs and the like include a reservoir for the drug as well as a permeable adhesive layer for maintaining the transdermal patch or the like on the skin or mucosa of a patient. A significant improvement in this field is represented by U.S. Pat. No. 4,573,996, which is seepage-resistant during use and thus eliminates prior problems of contamination which were previously encountered with such devices.
A continuing problem with such devices, however, relates to the overall handling of these patches, and more particularly to the need to maintain the transdermal patches in contact with the skin for extended periods of time. In such situations, even where highly effective adhesives are utilized, there remains a tendency for the adhesive to become less effective with time and use, and for the patch to eventually fall off. Furthermore, it is difficult to transfer the patch without reducing its effectiveness.
The search has therefore continued for more effective systems for applying film layers to the skin or mucosa of a patient, and for applying transdermal patches and the like to the skin of a patient.